Update multiple columns in MySQL but only when a value is not null -

i have mysql table multiple columns, a, b, , c.

i update columns using 1 sql statement. however, of columns can null.

so, if null, update b , c.

if , b null, update c.

and on, other combinations.

how can in 1 single statement?

thanks.

you can use if within update clause:

update test_update set a=if(a null, null, 'a2'), b=if(b null, null, 'b2'), c=if(c null, null, 'c2'); 

example run:

mariadb [test]> select * test_update; +------+------+------+ |    | b    | c    | +------+------+------+ | a1   | null | null | | null | b1   | null | | null | null | c1   | | a1   | b1   | null | | a1   | null | c1   | | null | b1   | c1   | | a1   | b1   | c1   | +------+------+------+ 7 rows in set (0.00 sec)  mariadb [test]> update test_update set a=if(a null, null, 'a2'), b=if(b null, null, 'b2'), c=if(c null, null, 'c2'); query ok, 7 rows affected (0.00 sec) rows matched: 7  changed: 7  warnings: 0  mariadb [test]> select * test_update; +------+------+------+ |    | b    | c    | +------+------+------+ | a2   | null | null | | null | b2   | null | | null | null | c2   | | a2   | b2   | null | | a2   | null | c2   | | null | b2   | c2   | | a2   | b2   | c2   | +------+------+------+ 7 rows in set (0.00 sec)